Miles or Kilometers for historical fiction?

I am writing a novel of historical fiction about the Second World War. It is written in the POV of several German and Russian characters but is intended for English readers. Which units of measurement should I use when referencing distance, weights and time? Miles or kilometers, pounds or kilograms, 24-hour or 12-hour time designations?

• I believe 24 hour time is fairly universal in militaries because it's unambiguous. As for distances, you could always use the units the POV characters in a particular scene would use (Miles for the British, Kilometres for the Germans, etc) I remember one book I read (The Machine Gunners) even made a plot point of unit confusion. A bunch of British kids managed to get their hands on a German machine gun from a crashed plane but when they tried to use it they mis-set the range because they thought it needed to be set in yards when it was actually in metres. Jul 24, 2018 at 12:33

It's not "history" but rather "geography" that determines whether you should use kilometers or miles.

If your characters are German or Russian, use kilometers, because that's what they use, even today. (Depending on the time, e.g. Tolstoy in the 19th century, a Russian might use "versts", which are just a bit more than a kilometer.)

On the other hand, if you were writing an American Civil War novel, use miles, because that's what nineteenth century Americans used.

• Yes. Use the units that your viewpoint characters use. Jul 7, 2016 at 20:43

If you're looking at this from the perspective of a set of characters talking to each other, it would depend on their background. If their country used metric, then they would have metric as their instinct. If you want them to 'convert' because of the presence of an American character, for example, you can do what we Canadians sometimes end up doing which is "It's about half a meter... hang on, two and a half centimeters per inch, it's about 20 inches." From that point you could have the "metric" character providing US Customary units or Imperial, or whatever (or the reverse).

At the end of the day, you don't want to break your reader out of the story. You don't want them to feel like you're ignorant of what was used, and you don't want to make things awkward. Doing something like this, or finding another means, allows you to have the transition to "what you assume your reader is most comfortable with." However, whenever they would come across "official documents" or they would receive orders, you could keep it in the "other" system, which would also allow you to create a sense of distance and formality about those issuing the orders.

I hope that helps.

I would just use kilometres, it's a fairly world-wide unit of measurement, known even in the English speaking world. Most people have a vague idea of how far it is even if they can't easily convert from kilometres to miles in their head - I imagine even more so if they are interested in military fiction.

Besides, don't (Didn't) even the American military use the slang "klicks" to mean kilometres? You'd often see it used in American media by American characters for an American audience - and they don't seem too bothered about the audience knowing exactly how many miles that is (not to mention what the hell a "klick" is)

Not sure if they did as far back as WW II but your audience are modern English speakers.

If exact distance is a factor, you could always add in extra information like ("so it will take fifteen minutes to get there").

The Metrification of the U.S. Military can be dated as far back as the 1918, when Klick became slang for Kilometer was introduced. Guns from 1957 onwards are in metric (legacy still use imperial measurments). Aircraft use pounds for ordinance, but most military vehicles are built to metric standards. U.S. Navy still uses inches for guns, and the submarine fleet still uses feet for depth and velocity and the "Kiloyard" for distance. Other wise the Navy and airforce use Nautical Miles for distance and Knots for speed, both of which are metric unites of measure. Civilian and NATO military aviation all collectively use feet for height.

With this in mind, the average U.S. reader will more than likely accept metric units as the accepted use in military jargon, even from their own troops.

• “Other wise the Navy and airforce use Nautical Miles for distance and Knots for speed, both of which are metric unites of measure.” — No, they are not. They are internationally used, and they are nowadays defined in terms of metric units (as are the US units, BTW; an inch is defined to be 2.54 centimeters), but they are not part of the metric system. Jul 23, 2018 at 16:33
• You're right. Misread of my source. Jul 23, 2018 at 16:39
• In aviation, I think Russia is the only country that doesn't measure altitude in feet, but in meters. Yes, even pilots in thoroughly metric countries might be flying at, say, 4,000 ft above ground, or at flight level 280 (FL280) which is (28,0)00 ft above the altitude where the atmospheric pressure is 1013.25 hPa. (The latter is a bit of a mouthful, so "flight level" is used for brevity.)
– user
Jul 23, 2018 at 17:39
• ICAO is the International Civilian Air Organization and is the governing body of international flights. Their membership includes 191 of the 193 nations of the UN (Dominica and Lichtenstein being the two non-signatories) and the Cook Islands (not a member state of the UN.). That pretty much cements Russia as using feet, at least on international flights. Jul 23, 2018 at 18:55

I am not versed in who used what when, so I can't tell you exactly what to use. Fortunately, I can tell you how to find out.

In most fiction, your write for your readers. So if your audience is German or Russian, you use the Metric System. If they are American, you use the US Customary System

In historical fiction, Germans or Russians would use the metric system, so they should do so within your novel. You can always include a conversion somewhere within your novel if the detail is important, or even just a vague description of the distance: "A field away," "A castle the size of a pigeon on the horizon," "a stone's throw."

However, when you the author are talking to the reader (ie, narration, no character is speaking), you should use the Us Customary Units. It might seem a bit jarring, so if possible, you might want to not use exact measurement units all the time. Rather, use descriptions like I included above, or simply things like, "arm's reach" and "a stride away" for short distances.

• Yes, I was thinking of this in terms of which method the narrator would use. Specifically, I've seen authors who write about war and battles use date and timelines, such as: Rhine River, 15 February, 1945, 16:30 HRS Thanks for your comments. I appreciate it. Jul 4, 2016 at 22:56
• Remember that you can mark the most helpful reply as the answer - it helps other people with the same question find the answer faster. Jul 6, 2016 at 18:19
• This answer, and particularly what you discuss in the third paragraph, reminds me of my old question on English Language & Usage about Multiple stone throws. Those who find this answer useful might want to also check out that one. (end shameless plug)
– user
Jul 23, 2018 at 17:35

I would say: In general, use the system familiar to your readers.

German officers during World War 2 presumably spoke German. But if I wrote an historical novel intended for American readers, I would give the dialog in English, for the obvious reason that most of my readers do not understand German. The reader understands that the dialog is intended to be a translation.

Likewise, I'd generally give units of measure in the Imperial system, because that is what the reader is familiar with.

I'd say this is borderline because most Americans are at least generally familiar with the metric system, so they wouldn't likely have serious trouble understanding the units that German officers would really have used.

There can be an issue if the actual numbers matter. For example, if I was reading a novel where a German character said, "Our reinforcements are still 13 miles away. 13 is proving a very unlucky number for us today", as a reader I might balk and say, "But wait, he would have really said 21 kilometers. Why would the character relate 21 kilometers to the unlucky number 13? This doesn't make sense." (Assuming Germans think of 13 as an unlucky number. Just making an example.)

I'd avoid using one set of units in dialog and another set in narration. I think that would get very confusing. Readers would have to convert back and forth to make sense of the story.